[Maxima-discuss] Stair function

[Pierre C. <pie...@ac...>]

Hello


I'd like to draw a stair function to illustrate what we called in france 
"Méthode des rectangles" :

I try this :

f(x):=1/(1+x);
E(f,x,n,a,b):=block(
     if x=b then return(f(b))
     else
     for i:1 thru n do if (x < a+i*(b-a)/n) then return(f(a+(i-1)/n))
);
E(f,0.19,10,0,1);
E(f,1,10,0,1);
E(f,0,10,0,1);

But

wxplot2d([f(x),E(f,x,10,0,1)], [x,0,1])$

give me an error : COERCE-FLOAT-FUN: no such Lisp or Maxima function: done

any idea to produce the function may be with no evaluation on each x ?

Thx